Starter for engines



Nov. 15, 1927. 1,648,946

M. B. JACKSON 5 TARTER FOR ENGINES Filed Jan- 25- 1926 Q 2* E "um;

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IWJ MIIHIHIII'III Patented Nov. 15, 1927.

I UNITED STATES PATENT OFFICE.

STARTER FOR ENGINES.

Application and January 25, 1926. Serial No. 88,780.

This invention relates to starters of the type disclosed in m prior application Serial No. 55,563, filed eptember th, 1925,'in which normally inoperative means for axis ally moving the pinion, after its teeth are rotated sufliciently to clear the teeth of the en.

gine gear, was shown The object of the present invention is to provide, in a device of the same general type, simple means for to engagement with the normally inoperative means whereby the latter is gradually rendered operative with the least possible rotary effect on the pinion.

I attain my object by providing one of the pinion or the shaft parts with a cam member adapted to engage a resilient member carried on the other of the said parts. When the starter pinion is in its normal or inoperative position the cam member is in engagement with the secured end of the resilient member or the part which carries it.

The resilient member is compressed by contacting' with and riding up the cam face when the starter motor is energized which 26 causes a relative rotary movement of the cam and resilient members. The construction 'of my starter is hereinafter fully described and illustrated in the accompanying drawings in which Fig. 1 is a longitudinal section of the starter showing the pinion and the resilient member in their inoperative positions, the

cam member being carried bythe pinion and v the resilient member by the shaft;

Fig. 2 a view similar to Fig. 1, partl broken away and showing the pinion teet in contact with the ends of the engine gear teeth, the resilient member being compressed;

Fig. 3 a cross section on the line 3-3 in Fig.1 a cross section on the line 4-4 in Fig. 2;

Fig. 5 a longitudinal section of part of the starter showin the pinion and the resilient member in t eir inoperative positions,

the cam member being carried by the shaft and the resilient member by the pinion; and

Fig. 6 a side elevation, partly in section, of

part of a starter showing the resilient memer formed .as a spring actuated plunger.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

1 is. an extended armature shaft of an electric motor 13 (only partly shown). On the end 1 of the shaft is secured a sleeve 2 having a long pitched triple thread 2' formed thereon and on the outer end of the sleeve is secured a collar 3.

A pinion 6 loosely threaded on the sleeve 2 is adapted to be axially moved into and out of mesh with a gear 7 connected with the crankshaft of an engine (not shown), the common practice being to secure this gear to the engine flywheel.

A resilient member formed as a bent spring finger 4 as shown in Figs. 1, 2 and 5, or a spring actuated plunger 4, as shown in Fig. 6, may be carried on either the collar 3 or the pinion 6.

This member is adapted to engage a cam member 8 which is carried on the other of the collar and pinion parts. Referring to Figs. 1 and 2, the resilient member is annular in shape and is secured on the inne face of the collar 3. A lip 45 formed on the member is adapted to be received in a groove 3 formed in the inner face of the collar and is retained therein by means of the inwardly directed flange or rim formed on a band 5 passed round the periphery of the collar and secured thereto. The spring finger portion 4 of the member is free of the band 5 and extends partly round the shaft. The free end 4 of the finger is convexly curved for engagement with the cam face'of the member 8 which, in this case, is carried by the pinion.

'As hereinbefore mentioned the pinion is loosely threaded on the sleeve. This permits a limited rotary movement of the pinion threads relative to the sleeve threads and permits the spring fin er 4 to be rotated relative to the cam mem ber 8, Figs. 1 and 2. This produces a pressure on the pinion tending to axially move it into mesh with the gear. In other words, the pinion threads are normally in contact with the sides a of the shaft threads 2 and when the shaft is set in, motion the threads thereof run ahead of the pinion threads. Due to the inertia of the pinion, the spring finger 4 also runs ahead of the cam member 8, carried on the pinion, so that the finger forces the pinion along the shaft. If the pinion teeth enter between the engine gear teeth the latter hold the pinion from rotation and the sides 6 of the shaft threads engage the pinion threads to axiall move the pinion farther alon the shaft. he threads also form a rotary rive connection between the shaft and pinion to drive the gear when the axial movement is stopped by the abutment 9.

If the teeth of the pinion and gear meet end to end, when the former is being axially moved by the finger 4; into mesh with the gear, the axial movement of the pinion towards the gear will be stopped but the rotary movement of the shaft relative to the pinion will continue so that the normally high or free end 4 of the finger 4 will be pressed back until the sides b of the shaft threads contact with the pinion threads and rotate the pinion teeth sufficiently to clear the teeth of the gear. The free end 4 is then free to spring back and force the pinion axially of the shaft and into mesh with the gear. By employing long pitched threads on the shaft and pinion the force tending to move the pinion rotarily on the shaft is greater than the force tending to move the pinion axially of the shaft so that the pinion teeth do not dig into the gear teeth if they meet end to end.

It will be noted in Figs. 1 to 5 that the spring finger l does not contact with the cam member 8 when the pinion. is in its normal or inoperative position and that only the free end 4 of the finger is adapted to contact with the cam face on the cam member 8. With this construction the spring finger is gradually compressed by a minimum amount of pressure which results in the least posslble rotary effect on the pinion. In other words the pressure tending to move the pinion axially of the shaft is a minimum at the beginning of the relative rotary movement and increases directly as the relatlve rotary movement is increased. M

The pinion is returned to its inoperative position, when the engine is started, in the following manner. The speed of the flywheel ear 7 when operated by the starter motor is less than its speed when the eng ne is started so that the instant the engine starts, the speed of the starter pinion, relative to the starter shaft, is increased. This causes the pinion to be threaded along the shaft to move it out of mesh with the gear. In this connection it will be noted that the pinion threads are first rotated relative to the shaft threads to bring the former into engagement with the sides a of the shaft threads so that the cam member 8 Wlll clear the free end of the finger 4: when it is being returned to its normal position.

In Fig. 5 the resilient member is carried on the pinion and-the cam member 8 is carried on the shaft. With this construction the collar 3 is not necessary.

In Fig. 6 the resilient member is formed as a spring actuated plunger 4* preferably carried by the collar 3 which is secured to the shaft. When the latter is set in motion,

the plunger is rotated relative to the cam member 8 and rides up its cam face. This gradually compresses the plunger spring 49 to operate the pinion in the same manner as the finger 4 operates it;

What I claim is:

1. In a starter for use with an internal combustion engine, the combination of a shaft; a pinion threaded on the shaft and having a limited rotary movement relative to the thread; a cam member carried by one of the shaft and pinion parts; and a bent spring finger carried by the other of the shaft and pinion-parts and having its free end only adapted to yieldingly engage the cam face of the said member, the said engagement commencing at the beginning of and continuing during a relative rotary movement of the pinion and shaft when the latter is set in motion whereby the axial pressure against the pinion increases directly as the relative rotary movement is increased.

2. In a starter for use with an internal combustion engine, the combination of a shaft having a long pitched thread; a pinion threaded on the shaft and having a limited rotary movement relative to the thread; a cam member carried by one of the said shaft and pinion parts and provided with a substantially helical cam face having a short pitch; and a bent spring finger carried by the other of the said shaft and pinion parts and having its free end only adapted to yieldingly engage the cam face of the said member, the said engagement commencing at the beginning of and continuing during a relative rotary movement of the pinion and shaft when the latter is set in motion where by the axial pressure against the pinion increases directly as the relative rotary movement is increased.

3. In a starter for use with an internal combustion engine, the combination of a shaft; a pinion threaded on the shaft and having a limited rotary movement relative to the thread; a rigid cam member carried by one of the shaft and pinion parts; and a bent spring finger carried by the other of the shaft and pinion parts and having its free end only adapted to yieldingly engage the cam face of the said member, the said engagement connnencing at the beginning of and continuing during a relative rotary movement of the pinion and shaft when the latter is set in motion whereby theaxial pressure against the pinion increases directly as the relative rotary movement is increased.

4. In a starter for use with an internal being adapted to yieldingly engage the cam face of the said member, the said engagement commencing at the beginning of and continuing during a relative rota movement of the pinion and shaft when t e latter is set in motion whereby the axial pressure against the pinion increases directly as the relative rotary movement is increased.

5. An engine starter drive mechanism including a rotatable shaft; a starter pinion mounted thereon for rotary movement therewith and for longitudinal movement thereof to mesh with a gear of the engine to be started, the shaft serving to rotate the pinion if the teeth on the latter meet end to end with the teeth on the ar; a cam member carried by one of sand shaft and pinion parts; and a resilient member carried by the other of the said shaft and pinion parts 20 and having one portion only thereof adapted to yieldi'ngly engage the cam member by a relative rotary movement of the said two members to cause such lon tudinal movement of the pinion when latter are rotated sufiiciently to clear the teeth of the gear.

Signed at Toronto, Ont, this 6th day of January, 1926.

MAUNSELL B. JACKSON.

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